Neurosurgical applications of tractography in the UK

Toescu, Sebastian; Hales, Patrick W.; Tisdall, Martin; Aquilina, Kristian; Clark, Christopher A.

doi:10.1080/02688697.2020.1849542

Cited by 7 publications

(13 citation statements)

References 25 publications

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“…In addition, tractography has poor reproducibility, with results depending on numerous factors [ 5 ]. All considered, it is perhaps unsurprising that there is hesitancy within the neurosurgical community to adopt intraoperative tractography [ 6 ], even as interest in intraoperative MRI [ 7 , 8 ] and tractography for surgical planning and navigation [ 9 , 10 ] grows. Currently intraoperative streamline tractography is mostly limited to the often outdated tools available in commercial navigation software [ 3 ].…”

Section: Introductionmentioning

confidence: 99%

Fibre tract segmentation for intraoperative diffusion MRI in neurosurgical patients using tract-specific orientation atlas and tumour deformation modelling

et al. 2022

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Purpose: Intraoperative diffusion MRI could provide a means of visualising brain fibre tracts near a neurosurgical target after preoperative images have been invalidated by brain shift. We propose an atlas-based intraoperative tract segmentation method, as the standard preoperative method, streamline tractography, is unsuitable for intraoperative implementation. Methods: A tract-specific voxel-wise fibre orientation atlas is constructed from healthy training data. After registration with a target image, a radial tumour deformation model is applied to the orientation atlas to account for displacement caused by lesions. The final tract map is obtained from the inner product of the atlas and target image fibre orientation data derived from intraoperative diffusion MRI. Results: The simple tumour model takes only seconds to effectively deform the atlas into alignment with the target image. With minimal processing time and operator effort, maps of surgically relevant tracts can be achieved that are visually and qualitatively comparable with results obtained from streamline tractography. Conclusion: Preliminary results demonstrate feasibility of intraoperative streamline-free tract segmentation in challenging neurosurgical cases. Demonstrated results in a small number of representative sample subjects are realistic despite the simplicity of the tumour deformation model employed. Following this proof of concept, future studies will focus on achieving robustness in a wide range of tumour types and clinical scenarios, as well as quantitative validation of segmentations.

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Section: Introductionmentioning

confidence: 99%

Fibre tract segmentation for intraoperative diffusion MRI in neurosurgical patients using tract-specific orientation atlas and tumour deformation modelling

et al. 2022

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“…The inner product between the orientation atlas and target FOD image provides an intuitive map of tract location and is A key finding in Toescu et al (2020) was the logistical barrier to deployment of tractography in neurosurgical units in the United Kingdom, as well as a lack of knowledge among neurosurgeons of the underlying choices in fibre modelling and tracking algorithms involved, which could lead to flawed interpretations of tractography reconstructions. We hope that the use of a predefined tract atlas in combination with readily automated registration and dMRI processing tools will go some way towards reducing that logistical burden, as well as aiding interpretation of the results.…”

Section: Discussionmentioning

confidence: 99%

“…In Toescu et al (2020) they were cited by neurosurgeons as the most frequently reconstructed tracts, followed by the corpus callosum.…”

Section: Streamline Free White Matter Segmentationmentioning

confidence: 99%

Fibre orientation atlas guided rapid segmentation of white matter tracts

Young,

Aquilina,

Seunarine

et al. 2024

Human Brain Mapping

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Fibre tract delineation from diffusion magnetic resonance imaging (MRI) is a valuable clinical tool for neurosurgical planning and navigation, as well as in research neuroimaging pipelines. Several popular methods are used for this task, each with different strengths and weaknesses making them more or less suited to different contexts. For neurosurgical imaging, priorities include ease of use, computational efficiency, robustness to pathology and ability to generalise to new tracts of interest. Many existing methods use streamline tractography, which may require expert neuroimaging operators for setting parameters and delineating anatomical regions of interest, or suffer from as a lack of generalisability to clinical scans involving deforming tumours and other pathologies. More recently, data‐driven approaches including deep‐learning segmentation models and streamline clustering methods have improved reproducibility and automation, although they can require large amounts of training data and/or computationally intensive image processing at the point of application. We describe an atlas‐based direct tract mapping technique called ‘tractfinder’, utilising tract‐specific location and orientation priors. Our aim was to develop a clinically practical method avoiding streamline tractography at the point of application while utilising prior anatomical knowledge derived from only 10–20 training samples. Requiring few training samples allows emphasis to be placed on producing high quality, neuro‐anatomically accurate training data, and enables rapid adaptation to new tracts of interest. Avoiding streamline tractography at the point of application reduces computational time, false positives and vulnerabilities to pathology such as tumour deformations or oedema. Carefully filtered training streamlines and track orientation distribution mapping are used to construct tract specific orientation and spatial probability atlases in standard space. Atlases are then transformed to target subject space using affine registration and compared with the subject's voxel‐wise fibre orientation distribution data using a mathematical measure of distribution overlap, resulting in a map of the tract's likely spatial distribution. This work includes extensive performance evaluation and comparison with benchmark techniques, including streamline tractography and the deep‐learning method TractSeg, in two publicly available healthy diffusion MRI datasets (from TractoInferno and the Human Connectome Project) in addition to a clinical dataset comprising paediatric and adult brain tumour scans. Tract segmentation results display high agreement with established techniques while requiring less than 3 min on average when applied to a new subject. Results also display higher robustness than compared methods when faced with clinical scans featuring brain tumours and resections. As well as describing and evaluating a novel proposed tract delineation technique, this work continues the discussion on the challenges surrounding the white matter segmentation task, including issues of anatomical definitions and the use of quantitative segmentation comparison metrics.

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“…In a recent survey conducted from 36 out of all 40 neurosurgical units in the UK and Ireland, 90% of the neurosurgical units use tractography regularly, and they are predominantly DTI-based reconstructions. Concerningly, many neurosurgeons remain unfamiliar with the underlying methods used to produce tractography visualisations (Toescu et al 2020). An alternative way to provide a snapshot of clinical practice is to look at relevant tractography surgical cohort reporting.…”

Section: Survey Of Neurosurgical Clinical Practicesmentioning

confidence: 99%

Diffusion MRI tractography for neurosurgery: the basics, current state, technical reliability and challenges

et al. 2021

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Diffusion magnetic resonance imaging (dMRI) tractography is currently the only imaging technique that allows for non-invasive delineation and visualisation of white matter (WM) tracts in vivo, prompting rapid advances in related fields of brain MRI research in recent years. One of its major clinical applications is for pre-surgical planning and intraoperative image guidance in neurosurgery, where knowledge about the location of WM tracts nearby the surgical target can be helpful to guide surgical resection and optimise post-surgical outcomes. Surgical injuries to these WM tracts can lead to permanent neurological and functional deficits, making the accuracy of tractography reconstructions paramount. The quality of dMRI tractography is influenced by many modifiable factors, ranging from MRI data acquisition through to the post-processing of tractography output, with the potential of error propagation based on decisions made at each and subsequent processing steps. Research over the last 25 years has significantly improved the anatomical accuracy of tractography. An updated review about tractography methodology in the context of neurosurgery is now timely given the thriving research activities in dMRI, to ensure more appropriate applications in the clinical neurosurgical realm. This article aims to review the dMRI physics, and tractography methodologies, highlighting recent advances to provide the key concepts of tractography-informed neurosurgery, with a focus on the general considerations, the current state of practice, technical challenges, potential advances, and future demands to this field.

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Neurosurgical applications of tractography in the UK

Cited by 7 publications

References 25 publications

Fibre tract segmentation for intraoperative diffusion MRI in neurosurgical patients using tract-specific orientation atlas and tumour deformation modelling

Fibre tract segmentation for intraoperative diffusion MRI in neurosurgical patients using tract-specific orientation atlas and tumour deformation modelling

Fibre orientation atlas guided rapid segmentation of white matter tracts

Diffusion MRI tractography for neurosurgery: the basics, current state, technical reliability and challenges

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